U.S. Secretary of State Mike Pompeo on Tuesday said Pyongyang had not returned to negotiations as quickly as Washington had hoped, though added he expected the road to the DPRK’s denuclearization to be a bumpy one.

Pompeo’s comments come as Washington’s point man on North Korea Stephen Biegeun arrived in South Korea earlier on Tuesday with the hope of restarting talks.

“Special Representative Biegun, who leads the negotiation effort on behalf of the United States, is actually in the region today, tomorrow,” Pompeo told CBS News in New York.

“We haven’t gotten back to the table as quickly as we